The beautiful orchids, Phalaenopsis pot plant,
have had the highest price among the ornament plants for a long time.
However, because of over-supply, the price decreased sharply in 2008.
Plants with low quality have been driven out the market. Only high
quality orchids are of benefit. This paper discusses the basic
techniques to produce high quality Phalaenopsis.

1.Special
characteristics of the organs for Phalaenopsis

The important organs for Phalaenopsis are the
roots, leaves and spikes.

1.1Roots

The functions of roots include fixing the plant in
the substrate and absorbing water and nutrients. The root contains
chlorophyll, so the natural color is green. Roots have the ability for
photosynthesis and assimilation. The adequate environment for roots is
moist (vapour) and not soaked with water.

The nutrients dissolved in water cannot be adsorbed
by roots directly. The nutrients are adsorbed with the vapour in the
air. The adequate substrates for Phalaenopsis must be able to
provide moisture, fresh air (oxygen) and nutrients.

If the pot material is transparent, light can pass
through the pot wall and provide the energy of photosynthesis. Healthy
roots are green and bright.

1.2Leaves

The most important organ for Phalaenopsis is
leaves. Leaves have the photosynthesis ability for carbon fixation and
the assimilation function to store the available carbon. Except of Ca
and Mg, nutrients can be adsorbed into leaves directly. The required
carbon sources for spikes and flowers are provided from leaves.

1.3Spikes

The natural color for spikes is green. Spikes contain
chlorophyll and have the same photosynthesis ability same as for leaves
and roots. However, the assimilation materials are not sufficient for
development of spikes and blossoms. So the required dry matter for
spikes and blossoms is provided by leaves.

The priority of dry matter distribution for
Phalaenopsis differs from that of other plants. Roots are the first
to obtain dry matter. The ranking of dry matter distribution is roots＞leaves＞spikes＞blossoms.

2.Coexistence
of vegetable and reproductive phase

Most orchids have vegetative and reproductive stages.
The plants at the vegetative stage are in the state of growing and
developing, and plants at the reproductive stage are in the state of
spiking and flowering. The distinction between the two stages is so
obvious for many orchids. Oncidium is a typical orchids. At the
vegetative stage, the dry matter is produced and stored in pseudobulbs.
At the reproductive stage, the leaves stop the photosynthesis function,
and the required nutrients of spikes and blossoms are taken from
pseudobulbs.

Phalaenopsis has
special characteristics for vegetative and reproductive stages. Plants
developing from tissue culture plantlets to reach the mature stage, they
are in the vegetative stage. As these mature plants are moved to a
cooling environment for spiking, they are in the reproductive stage
until the length of spike reaches to 3-5 cm. However, two stages coexist
in the flowering phase. The spikes are lengthened continuously and buds
appeared (reproductive stage). The leaves accumulate dry matter and send
it to spikes and blossoms (vegetative stage); that is, the required dry
matter of spikes and blossoms are taken from leaves. The leaves need to
supply the dry matter to spikes and blossoms in the flowering stage.

The microclimate control and fertilization work are
important at the flowering stage. The leaves must be maintained at
optimal day and night temperature. The light intensity and period are
also important. The nutrients need to be supplied correctly. So the
leaves must accumulate enough dry matter and send it to spikes and
flowers to ensure flower quality.

3.Factors
affecting Phalaenopsis quality

3.1Genotype

The genotype characteristics of the Phalaenopsis
variety include flower color, pattern, flower size, flower number,
numbers of spike, multi or no branches, and stem height, etc.

3.2Healthy conditions

The plant must mature enough before cooling. Enough
dry matter must be stored in plants. The plants must be protected
against disease, pest damage, viruses, chemical damage and salt
accumulation in substrate.

Figure 1. These plants are in good
conditions for cooling treatment

3.3Environment

The environmental factors, such as day temperature,
night temperature, relative humidity, light period and intensity must be
kept at the optimal range.

The interaction of genotype, health conditions and
environment needs to be emphasized. The genotype decides the maximum
possible expression for flower quality. For example, the orchids with
little white flowers, P. amabilis, containd genes for more twenty
flowers. If the plant is mature enough and the cooling environment is
appropriate, the grower can obtain more than twenty flowers for each
plant. However, the number of flowers will decrease if the plant is
immature, or has been damaged by disease or pests, or if the temperature
or light intensity are not maintained well.

The effect of microclimate on other flower qualities
is described below:

3.3.1Temperature difference of vegetative stage and cooling stage

The numbers of spikes is affected significantly by
the temperature difference between the vegetative and cooling phases.
The "Mansanfong" variety is used to illustrate the effect of temperature
difference on number of spikes. The adequate day and night temperature
for the vegetative stage is 28℃and 26℃,
respectively. If the cooling temperature of day and night is kept at 25℃and
20℃, 100％ these
plants have one spike. As the cooling temperature of day and night is
maintained at 23℃ and 20℃,
40％ of these plants have spikes and 60％
of these plants have one spike. At the environment of 20℃
day temperature and 18℃ night temperature,
100% of these plants have two spikes.

3.3.2The difference between day and night temperature at flowering
stage

The symbol DT represents the difference between day
and night temperature at the flowering stage. With increasing DT, the
length of spikes (or stems) is lengthened. With decreasing DT, the
length of spikes (or stems) is shortened.

Figure 2. DT increase, the length of
spikes is too long

3.3.3Day temperature at flowering stage

If the day temperature at the flowering stage is the
same or higher than that of the vegetative stage, a leaf will appear in
the stem. It is called as “Keiki’s”. Despite the day temperature not
being higher than the temperature of vegetative stage, it is still
higher than the normal condition and the high day temperature will
reduce the flower quality. The position of the first bud is heightened,
all buds will be blocked up in the end of stem, the flower color will
fade and the number of branches is decreased.

Figure 3. Keiki’s of the Phalaenopsis

Figure 4. All buds will be blocked up in
the end of stem because the day temperature is too high

3.3.4Night temperature at flowering stage.

If the night temperature at the flowering stage is
higher than the adequate condition, the number of blossoms is decreased
and the flower size is reduced.

4.Diversity
characteristics of Phalaenopsis varieties.

The required qualities are two or more spikes,
multi-branching, bright color, and 40-to 75-cm height in The
Netherlands. According to the Culture Guide of Floricultura b.v.,
the adequate environment conditions for Phalaenopsis are as
follows:

Table 1. Adequate environment conditions
for Phalaenopsis

Day temp

Night temp

Light intensity

Vegetative phase

28℃

26℃

4000-6000lux

Cooling

20℃

18℃

7000-8000 lux

Flowering phase

23℃

20℃

7000-8000 lux

However, the growers usually find that many varieties
cannot produce the required quality according to these environment
conditions.

In the orchids greenhouse, the leaf colour of some
varieties turned red and dark (Figure 5) in The Netherlands. Some
varieties are still induced to spike at the growing regions (day temp.
28℃, night temp. 26℃) (Figure 6). Some varieties cannot induce any
spikes at the cooling regions (day temp. 20℃, night temp.18℃) (Figure
7).The reason for these results can be explained by the diversity of
Phalaenopsis varieties.

Figure 5. Leaves colour of different
varieties was found that turned into red and dark at the
same light level

Figure 6. Some
varieties still be induced to spike at the growing regions

(day temp. 28℃,
night temp. 26℃)

Figure 7. Some varieties can not be
induced any spikes at the cooling regions

(day temp. 28℃, night temp. 26℃)

5.Classification
of the Phalaenopsis characteristics

5.1According to the culture temperature

Seven types of
Phalaenopsis varieties are classified by optimal day and night
temperature for the vegetative stage:

A. 31-33℃ / 25-26℃, such as V3, P. Sogo Yukidian

B. 28-30℃ / 24-25℃, such as P. amabilis

C. 28-30℃ / 21-22℃, such as D. Queen Beer

D. 24-25℃ / 20-21℃, such as P. Taipei Gold

E. 21-22℃ / 18-19℃, such as P. Fortune Saltzman

F. 26-31℃ / 21-24℃, such as D. Sin-Yuan Golden
Beauty

5.2According to light intensity

The required light intensity of the Phalaenopsis
is influenced by the growing stage. The required light intensity of
mature plants is usually higher than that of small size plants. A
typical variety of big white flower, V3, P.
Sogo Yukidian is used to illustrate the
levels of light intensity in different stages.

Table 2. The require light intensity at
different stages for P. Sogo
Yukidian

4.0
'' pot

25000
lux

3.0
'' pot

18000
lux

2.0 '' pot

10000 lux

flask

5000 lux

The effects of environment on the flower quality are
presented as the following case.

The beauty blossom of three spikes is showed in
Figure 8. This variety is grown at Pingtung County, southern Taiwan.
High day and night temperature (32℃/26℃) and high light intensity (25000
lux) was provided. Then plants were sent to the cooling room (day and
night temperature was 23℃ /18℃, light intensity was 28000 lux). As the
healthy and mature plants were placed in cooling rooms, three spikes are
induced. Thus larger and more beautiful blossoms were produced.

Figure 8. The beauty blossoms of three
spikes for V3, P. Sogo Yukidian

Some plants were transported to the New York, USA.
The microclimate in the greenhouse for the growing stage was 22℃ (day)
and 20℃ (night). The light intensity was maintained at 16000 lux. In
this condition, these plants did not have the enough sources for
photosynthesis. The accumulated dry matter was insufficient for further
utilization. With decreasing temperature with the season change and the
spikes were induced. The quality of spikes and blossoms did not
appropriate for market requirement.

Figure 9. The quality of spikes and blossoms
of V3, P.
Sogo Yukidian
in New York

From the illustration of above case, the important of
the characteristics of variety need to be emphasized, which explains why
many varieties of Phalaenopsis have been sent to The Netherlands, some varieties had
excellent flowering quality. However, many varieties did not appear
accepted quality.

6.
Selection of the adequate varieties for The Netherlands

6.1The greenhouse microclimate

The microclimate of the greenhouse for
Phalaenopsis for The Netherlands is described in Table 1. The day
and night temperature are 28℃ and 26℃ for the vegetative stage and 20℃
and 18℃ for the cooling phase. So the selection of varieties of
Phalaenopsis to provide to this country need to meet the
requirements of temperature and light intensity listed in the Table 1.

6.2Required of variety for The Netherlands

The basic requirements of varieties are the genotype
and plantlet conditions

The genotype and others conditions of adequate
varieties are as follows.